Interval Notation
Throughout this reference, scale interval patterns are shown as sequences of steps. Each step tells you how many semitones to move up from one note to the next.
The numbers shown in the Intervals row on the Info page are the raw semitone counts. T = 2, S = 1, A2 = 3.
The 12 Keys
Western music is built on 12 notes, each a semitone apart. Every scale, chord and arpeggio in Piano Scales Lab can be played starting from any of these 12 root notes.
Major Scale
The major scale is the foundation of Western tonal music. It has a bright, settled sound and is the starting point for most music theory.
Interval pattern (T = tone, S = semitone):
| Key | Notes |
|---|---|
| C Major | C D E F G A B |
| G Major | G A B C D E F♯ |
| D Major | D E F♯ G A B C♯ |
| F Major | F G A B♭ C D E |
Natural Minor Scale
The natural minor scale has a darker, more melancholic sound than major. It uses the same notes as its relative major but starts on the 6th degree.
Interval pattern:
Harmonic Minor Scale
The harmonic minor raises the 7th degree of the natural minor by a semitone. This creates a stronger pull back to the root and gives the scale its distinctive exotic sound. The gap between the 6th and 7th degrees is an augmented 2nd (A2) — three semitones — which is the characteristic sound of this scale.
Interval pattern:
Melodic Minor Scale
The melodic minor raises both the 6th and 7th degrees when ascending, then reverts to natural minor when descending. Raising both degrees smooths out the awkward augmented 2nd leap of the harmonic minor, making the ascending line easier to sing and play.
Ascending intervals:
Descending: same as natural minor, played in reverse. Switch between ASC and DESC on the Scales page to see both.
Pentatonic Scales
Pentatonic scales use five notes per octave rather than seven. They are widely used in classical exam syllabuses, folk music and pop. Because they avoid the more dissonant intervals, any note in the scale tends to sound good over the corresponding chord.
Major Pentatonic
The major scale with the 4th and 7th degrees removed. Bright and versatile.
Minor Pentatonic
The natural minor scale with the 2nd and 6th degrees removed.
Both pentatonic scales are shown over one octave in the app, following standard ABRSM practice.
The Relative button works for pentatonic scales — C Major Pentatonic and A Minor Pentatonic share the same five notes.
Chromatic Scale
The chromatic scale includes all 12 semitones within an octave. Every note is a semitone apart. Because it uses every note equally, the chromatic scale has no key signature and no relative or parallel counterpart.
Interval pattern: all semitones — S S S S S S S S S S S S
Fingering rule: finger 3 on every black key, finger 1 on most white keys, finger 2 used at E–F and B–C where two white keys sit adjacent with no black key between them.
Arpeggios
An arpeggio is a chord played one note at a time. The app covers major and minor arpeggios over two octaves.
Major arpeggio intervals (root, major 3rd, perfect 5th):
Minor arpeggio intervals (root, minor 3rd, perfect 5th):
The numbers here are raw semitone counts: 4 = major third, 3 = minor third, 5 = perfect fourth (completing the octave).
Relative and Parallel Keys
Relative keys
A major key and its relative minor share the same notes and key signature. C Major and A Natural Minor are relatives — both use only the white keys. The relative minor starts on the 6th degree of the major scale (9 semitones up, or 3 semitones down).
Parallel keys
Parallel keys share the same root note but have different notes. C Major and C Natural Minor are parallel — both start on C but use different scales.
The Relative and Parallel buttons in the app work for all scale types including pentatonic. They can also be used to queue key changes during playback.
Key Signatures
A key signature tells you which notes are sharpened or flattened throughout a piece. It appears at the start of each line of music on the staff, after the treble or bass clef.
Sharps are always added in this order: F♯ C♯ G♯ D♯ A♯ E♯ B♯. Flats are always added in the reverse order: B♭ E♭ A♭ D♭ G♭ C♭ F♭.
| Sharps | Key | Flats | Key |
|---|---|---|---|
| 0 | C Major / A Minor | 0 | C Major / A Minor |
| 1 (F♯) | G Major / E Minor | 1 (B♭) | F Major / D Minor |
| 2 (+ C♯) | D Major / B Minor | 2 (+ E♭) | B♭ Major / G Minor |
| 3 (+ G♯) | A Major / F♯ Minor | 3 (+ A♭) | E♭ Major / C Minor |
| 4 (+ D♯) | E Major / C♯ Minor | 4 (+ D♭) | A♭ Major / F Minor |
| 5 (+ A♯) | B Major / G♯ Minor | 5 (+ G♭) | D♭ Major / B♭ Minor |
| 6 (+ E♯) | F♯ / G♭ Major | 6 (+ C♭) | G♭ / F♯ Major |
The Info page in the app shows the key signature for the current scale as a treble clef staff, with the correct sharps or flats in their standard positions. Minor scales share the key signature of their relative major.
The chromatic scale has no key signature — it uses all 12 notes so no key signature applies.
Chords and Progressions
A chord is three or more notes played together, built by stacking intervals. The Chords page in the app shows every chord in the current key with inversions and a library of progressions to loop.
Triads
The chords built on each degree of a major scale follow a fixed pattern:
| Degree | Roman numeral | Quality |
|---|---|---|
| 1st | I | Major |
| 2nd | ii | Minor |
| 3rd | iii | Minor |
| 4th | IV | Major |
| 5th | V | Major |
| 6th | vi | Minor |
| 7th | vii° | Diminished |
Seventh Chords
Seventh chords add a fourth note a 7th interval above the root. The app includes four types:
| Type | Symbol | Intervals | Character |
|---|---|---|---|
| Major 7th | maj7 | 4 + 3 + 4 | Warm, jazzy |
| Dominant 7th | 7 | 4 + 3 + 3 | Bluesy, tense |
| Minor 7th | m7 | 3 + 4 + 3 | Mellow, soulful |
| Diminished 7th | °7 | 3 + 3 + 3 | Dark, dramatic |
Inversions
An inversion is a chord with a note other than the root at the bottom. Triads have root, 1st and 2nd inversions. Seventh chords have root, 1st, 2nd and 3rd inversions.
Fingering Numbers
| Number | Finger |
|---|---|
| 1 | Thumb |
| 2 | Index finger |
| 3 | Middle finger |
| 4 | Ring finger |
| 5 | Little finger (pinky) |
Fingering shown in the app is based on standard classical piano conventions. You can view and customise fingering for any scale in the Fingering Editor.